Failing to add MCP server even though in setup tools are listed and visible - 424 failed dependancy #251

Tal8JB · 2025-12-14T09:47:53Z

Tal8JB
Dec 14, 2025

Using microsoft foundry extension in VScode to create and agent and adding MCP tool it.
When adding the mcp it seems to be working and tools are being retrieved and listed.
But when starting to work with the agent itself getting this error, not sure why this is happening.

Can you help ?

hund030 · 2025-12-16T06:00:47Z

hund030
Dec 16, 2025

Hi @Tal8JB , the error seems like caused by your server connection. Could you verify your MCP server available with simple client code?
For example:

from openai import OpenAI

client = OpenAI()

resp = client.responses.create(
    model="gpt-4.1",
    tools=[
        {
            "type": "mcp",
            "server_label": "test",
            "server_url": "your_mcp_server",
            "require_approval": "never",
        },
    ],
    input="test",
)
print(resp.output_text)

Also, I found a possible solution to your issue, you can reference to jlowin/fastmcp#855 (comment)

2 replies

Tal8JB Dec 17, 2025
Author

Hi @hund030 , thank you for responding.
My MCP is already running in stateless as described in jlowin/fastmcp#855 (comment)

It seems that the issue is network related.

I have configured our AI Foundry with Network injection for it to outbound from our private vnet because the MCP is hosted in our internal network as an Azure Container app.
I found that the agent is unable to resolve our agent internally it tryis to resolve it public address even though everything is setup correctly and the MCP is resolvable internally from that same vnet we're injecting to foundry, so it looks like a bug... :(

hund030 Jan 8, 2026

Service team is following this issue. cc @yaoleo34 for any updates.

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Failing to add MCP server even though in setup tools are listed and visible - 424 failed dependancy #251

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Microsoft Foundry

Failing to add MCP server even though in setup tools are listed and visible - 424 failed dependancy #251

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Tal8JB Dec 14, 2025

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hund030 Dec 16, 2025

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Tal8JB Dec 17, 2025 Author

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hund030 Jan 8, 2026

Tal8JB
Dec 14, 2025

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hund030
Dec 16, 2025

Tal8JB Dec 17, 2025
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